CD44 and breast cancer: The findings show that human homeobox B9 (HOXB9), a key transcription factor that promotes metastases in lung and breast cancers [25, 26], is involved in enhanced metastatic capacity and resistance to physical/chemical castration therapy in the PCa model caused by orthotopic implantation of ALDH+ CD44+ CXCR4+ CD24+ subpopulation.